Gabriel a



(No Model.)

G. A. BO'BRIGK.

SCHOOL DESK. Patented May 30, 1893..

WW d 1 ilornegy arrangement of the UNITED I STATES GABRIEL A. BOBRIOK, OF NEW YORK, N. Y.

SCHOOL-DESK.

SPECIFICATION forming part of Letters Patent No. 498,703, dated May 30, 1893.

Application filed May 4, 1892.

Serial No. 431,753. (No model.)

To all whom it may concern.-

Be it known that I, GABRIEL A. BOBRIOK, a citizen of the United States, and a resident of New York, in the county of New York and State of New York, have invented certain new and useful Improvements in SchoolDesks and Chairs; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specification, and in which Figure l is a sectional view, on a vertical plane, of a school desk of my improved construction. Fig. 2 is a similar view of my improvement as applied to a chair, but showing certain modifications in the construction and operating parts; and Fig. 3 is a cross section through the stationary tubular standard and movable support, on line x-cc in Fig. 2.

Like letters of reference denote ing parts in all the figures.

This invention relates to school furniture, and has for its object to simplify, strengthen, and cheapen the construction of the mechanism for effecting the vertical adjustment of the desk-top or chair-seat, (as the case may be) andkeeping the same in its adjusted position.

To this end, my improvement consists in the detailed construction and combination of parts of the adjusting mechanism as will be hereinafter more fully described and claimed.

On the accompanying drawings, I have correspond- -shown, in Fig. 2, my improvement as applied to a school seat or chair; but the modified construction shown in that figure may be applied to the desk shown in Fig. 1, or vice versa.

Referring to the drawings, the letter A designates the desk-top, A the chairseat, and B the stationary tubular upright or standard used with both, which is screwed or bolted to the floor in the usual manner. To the under side of the desk or seat is fastened the adjustable bearing or support 0, which slides loosely in the socket of the tubular fixed standardB. This adjustable support or bar has on one side a longitudinal groove or channel.

D, and on the side opposite it is cut or cast with a vertical row of notches forming teeth, E, which do not, however, project beyond the solid parts of the bar; Fastened in the upper open end of the standard B is a catch, F, the inner end 0fv which projects into the hollow interior of the standard, so as to enage, under certain conditions, with the teeth of the vertically movable bar or support 0. This catch or retaining pawl F may be constructed and applied in various ways: For example, it may be simply a short flat piece of tempered steel fastened in the open mouth or top of the tubular standard by a screw, G, as illustrated in Fig. 1; or it may be a steel screw screwed into a threaded hole in the standard and furnished with a small nut-lock, or washer g, to hold it firmly in place, as shown in Figs. 2 and 3. This last-named construction affords an easy means for taking up wear on the inner end of the retaining pawl by permitting of its adjustment as occasion may require. Within the tubular standard, some distance below this retaining pawl and on the opposite side thereof, I may place a spring, or spring-bearing, H, which bears or presses with its free end against the slotted side of the movable support 0. This device maybe either in the nature of asimple leaf-spring, as shown in Fig. 1, with one end fastened, byascrew h, in the standard, and its free end pressing against the sliding bar,- or it may be a block or bearing, as illustrated in Fig. 2, having a coiled spring around its stem which presses it against bar Oon the side opposite to its toothed part. But this spring, in any of its forms, is not a necessary adjunct of, or condition to, the successful operation of my invention, and may be dispensed with, ifrdesired. Moreover, this spring device may be used independent of a notched bar 0 and retaining pawl F, and will, when so used in combination with a vertically adjustable smooth bar 0, (1'. e. a bar without notches) form a separate invention for which a separate application for Letters-Patent will be duly filed. It is here referred to merely as an (sometimes desirable) adjunct or auxiliary to the other parts of my improvement.

The upper part of the stationary standard B is reinforced so as-to form bearings, 11 t" of sufficient thickness and strength for the binding-screws I and I, the inner ends of which project into and can be made to bear or bind against the bottom of the longitudinal groove D. These screws form the essential means by which the desk-top or chair-seat (as the case may be) is permanently fastened, in its adjusted position, upon the fixed standard B; the notches and teeth in bar (J forming, in conjunction with the retaining-pawl F, merely a temporary hold or fastening, (contributing, however, also to the desk-top and its depending bar while these are being adjusted for a permanent position, vertically.

Having in the foregoing described the con struction of this device, I shall now proceed to describe the method or manner of operating it, which is briefly as follows:

If it is desired to raise the desk-top or chair seat (as the case may be), the binding screws I and I are first loosened, by a wrench or key applied to their squared heads, so that the grooved bar 0 will have some play or lateral motion in its socket. By now taking hold of the desk at or near its inner end (i. e. the end next to the seat) it will be tilted slightly for-.

ward, as indicated in dotted lines in Fig. 1, so as to disengage or release the series of teeth E from the inner end of pawl F. In this position the desk-top (or chair-seat) may be easily lifted and raised, to its desired elevation, and by now letting go of the same, it will, owing to the preponderancy of weight on the lifted side, tip or tilt back into the position shown in full lines, in which position the teeth E willengage and interlock with the projecting inner end of the catch or retaining-pawl. .By then tightening-up the binding-screws I and I, the movable supporting bar O, and will be fastened permanently (for the time being)'in its adjusted position. To lower the desk-top or chair-seat, this operation is simplyv reversed.- It will be seen that after the binding screws have been loosened, the -mov-. able stem or support 0 has sufficient play to permit of its always being tipped or, tilted Whether raised or lowered-so as to clear, with its notched or toothed side, the inner end of the retaining-pawl F; but the moment the hands are removed from the desk or seat, the preponderancy of weight on one side will so tilt the desk or seat, and with itthe notched bar'G, that its teeth E will instantlyv engage and interlock with the inner end of the pawl, the lower binding screw 1, serving as the fulcrum for the bar. By then adjusting the retaining-uscrews I and 1, causing them to bind with their inner ends firmly against the grooved side of the bar, the desk-top or chairseat will be firmly locked and held in its adj usted position, in which it will remain until occasion shall arise to readjust it, either up or down.' 7 j In adjusting the binding screws to lock the the permanent fastening) for with it the desk-top or chair-seat,

inner end of the pawl.

bar 0, the upper screw I, must be adjusted first, for if the lower screw 1, were adjusted first, it would tend to throw the bar out of engagement with the catch F, and allow the top or seat A, to fall. In fact so far as serving as a binding screw is concerned,thelower screw I, could be object being to form a fulcrum for the bar 0, so that the latter will fall or tilt by gravity to engage with the catch.

The essential novelty of my improvement consists in the gravitating or tilting (tipping) of the desk-top or chair-seat into a self-lockin g position, whereby the same will automatically assume such a position that its sliding bar or support 0 will of itself, and without any effort on the part of the operator, engage or interlock with the retaining-pawl F. The simple act of lifting the desk-top I or chairseat (after the binding screws 1- and I" have been loosened) results in the tipping forward of the sliding support 0, which disengages its dispensed with, its principal teeth from pawlF; and reversely the release a of the desk-top or chair-seat results in the tipping or tilting of bar 0 backward within its socket, so' that its teeth will engage the This pawl is not meant to be the chief or permanent fastening for the desk-top or chair-seat, by itself alone, but it will immediately arrest further movement of bar 0 in a downward direction, and

by them, as the next step in the act of adjustment, tightening-down the screws I and I the elevation'of the desk-top or chair-seat is effected permanently and fixedly to conform to the requirements of any given case. And it is this which forms the essence and novelty of my present application for Letters'Patent.

The object of the spring II, when used in combination with the tilting bar 0, is to form a cushioned bearing for the same as it is beingtilted forward against the spring, in the position shown in dotted lines, and it also forms a frictional bearing against the bar as this is moved up or down in its socket. But it may be dispensed with, if desired, or used in a different combination, which will form the subject of anotherapplication.

Having thus described my invention, I claim and desire to secure by Letters Patent of the United States I I 1. The combination ofthe tubular standard, the vertically movable supporthaving loose lateral play therein and provided with a row of teeth on one side, the retaining pawl adapted to engage with said teeth, and the binding screws in vertical alignment with each other, and their inner ends bearing against said support, and one of said screws serving as a fulcrum for said support, substantially as and for the purpose specified.

2. The combination of the stationary tubular standard, the vertically movable support having loose lateral play therein and provided with .a row of teethon one side, and a longitudinal groove on the side opposite, the retaining pawl adapted to engage said teeth, In testimony that I claim the foregoing as the spring secured to the standard and bearmyown I have hereunto aflixed my signature IO ing against the support, and the binding in presence of two witnesses.

screws in vertical alignment with each other,

5 their inner ends bearing against said support GABRIEL BOBRICK' and the lower screw serving as a fulcrum Witnesses: therefor, substantially as and for the purpose LOUIS BAGGER,

specified. BENNETT S. JONES. 

